1. Field Of The Invention
This invention relates to a device for precisely positioning or orienting a sheet of glass or other generally rigid planar material as a multiplicity of like sheets, in sequence, are moved from a first position to the device to be positioned or oriented by the device, and are then transferred by another device to a second position where a machining or other processing operation is to be performed thereon.
2. Description of the Prior Art
U.S. Pat. No. 4,955,763 (Delventhal and Grosjean), which is assigned to the assignee of this application, discloses a machine for drilling holes in a sheet of a generally rigid planar material, such as a glass sheet. In a typical production operation utilizing such a machine, a series of like rigid sheets, in sequence, is presented to the machine to have holes drilled therein. The rigid sheets are delivered to the machine from a source of such sheets, for example, by a conveyor or other transfer device.
During the delivery of individual sheets to a drilling machine or other machine or processing device, the sheets are subject to becoming misaligned from a desired alignment. This can be troublesome, and a misaligned sheet, when presented to a drilling machine such as that of the aforesaid '763 patent, or other machine or processing device, can wind up having holes drilled therethrough at improper locations, for example. Thus, when the accuracy of the locations of drilled holes in a finished sheet is important, or when the accuracy of the location of any other machining or processing step in a finished rigid, sheetlike article is important, each article must be precisely adjusted or oriented in its position before it is presented to the drilling machine or other machining or processing device.
The problem of adjusting the positions of sheets is even more difficult to deal with when the machine or device is to be used to process sheets of different dimensional characteristics, for example, when it is to be used to drill holes in different types or sizes of glass sheets. Under these circumstances, the sheet positioning device itself must be capable of being rapidly and accurately adjusted in its operating characteristics as the dimensional characteristics of the sheets being processed change from time to time, which is quite common in a production operation.
Certain prior artisans have recognized the desirability of providing adjustable devices for positioning or orienting rigid sheets, in sequence, during the processing of the sheets. For example, U.S. Pat. No. 4,228,993 (Cathers) discloses a vacuum actuated sheet transporting device which purports to be capable of performing an orienting step on each sheet in conjunction with the transporting step. However, the device of the Cathers patent lacks the degree of adjustability which is required in many manufacturing and processing operations.